Conventionally, automobile exterior parts, such as door sash, were directly coated with hardening resin paint such as a melamine resin, an isocyanate resin and a urethane resin, depending on materials of the parts, in order to provide the parts with scratch resistance, weather resistance, durability, stain resistance, corrosion resistance and design.
Housings of household appliances were directly coated with hard coat paint of an ultraviolet curable acrylic resin, in order to provide the housings with scratch resistance, durability, stain resistance and design.
However, such direct coating is associated with such problems that many steps, such as masking of areas not to be coated, coating, hardening and finishing, are necessary; preservation of work environment and management for safety and health are necessary in handling a solvent for paint; skill is necessary for forming a uniform and defect-free coating; and spray coating limits variety of design. Further, the ultraviolet curable hard coat paint is easily deteriorated by ultraviolet and, therefore, does not provide sufficient weather resistance.
Therefore, it was proposed to use a decorative film instead of the direct coating (see Patent Literature 1). The use of a decorative film solves the problems on workability, environment safety and design which occur in the direct coating. However, the film is poor in scratch resistance, weather resistance, durability, stain resistance and corrosion resistance.
A hardened product of a polydimethylsiloxane type copolymer having polycaprolactone and polysiloxane incorporated into a backbone of the compolymer was proposed as a material for a paint film having an increased scratch resistance (see Patent Literature 2). However, its scratch resistance, weather resistance, durability, stain resistance, corrosion resistance, bending durability, curved surface-following property, and impact resistance are not yet enough.
Patent Literature 1: Japanese Patent Application Laid-Open No. 2003-118061
Patent Literature 2: Japanese Patent No. 3999411